Various types of analog to digital converters exist to perform high-fidelity conversion of analog signals into digital form. Generally, such analog to digital converters accept as input a continuous analog signal and then provide, as output, a digital signal that corresponds to some measured aspect of the continuous analog signal. Although the measured aspect of the continuous signal is typically amplitude, the measured aspect may represent other features of the signal. In some instances, the continuous analog signal is a voltage signal, and in other instances, the continuous analog signal is a current signal. The produced digital signal is by definition discrete in time and discrete in amplitude.
Various types of analog to digital converters exist, each with varying circuit design. Some of these analog to digital converters include successive-approximators, integrators (including Δ-Σ converters), flash, and subrangers. Each type of analog to digital converter has a characteristic that may make its application beneficial to users based at least on one of its linearity, resolution, bandwidth, cost, and signal to noise ratio.
One general problem with analog to digital converters is that the conversion process introduces noise. Noise can greatly interfere with the output signal, and it may result in severe signal degradation or signal loss. Signal to noise ratio (SNR) expresses the accuracy of the digital output relative to the amount of noise that the analog to digital conversion process has introduced; so customers who require analog to digital converters with low noise on the signal select converters with high signal to noise ratios (SNR). In some converters, the noise may be filtered out of the signal, but the later filtration process takes additional time, which is not often desirable when fast conversion speed is also desired. The invention presented provides a solution to cope with excessive noise without extra filtering by encoding the desired analog signal on a stochastic signal prior to the conversion process. Furthermore, the invention provides high-fidelity conversion of the signal based on the number of samples that can be taken. The invention presented may be especially advantageous as an alternative to DC or low bandwidth analog to digital converter topologies.